1. Field of the Invention
This invention relates to mirrors which incorporate oscillating wipers to keep the mirrored surface visually clear. It involves an assembly which includes an oscillating drive mechanism utilizing a helical screw in such a fashion as to be easily manufactured and reliable in use. The helical screw may include progressively flaired reversing grooves and nut and tanged cylinder members. The entire drive mechanism may be housed in a sealed environment to promote reliability and durability.
2. Description of the Related Art
In 1959, U.S. Pat. No. 2913754 was granted to Vander Zee for a wiping device for outside rearview mirrors. This wiping device utilized rotational oscillation to drive a wiper connected at only one point to the oscillating mechanism.
Boyanich was granted U.S. Pat. No. 3526920 for a rearview mirror wiper. This invention improved upon the Vander Zee patent in that the wiper was attached at two points and was not driven through rotational oscillation. It did, however, utilize slot and pinion members for transmitting the oscillation to the wiper mechanism. No means was provided to seal the drive mechanism.
Laprairie described a rearview mirror and rotatably wiped enclosure in U.S. Pat. No. 3612647. This patent involved a housing in which the wiper did not contact the mirrored surface, but rather contacted and wiped a cylindrical transparent housing surrounding the mirrored surface.
Pittman through U.S. Pat. No. 3685087 described a rearview mirror wiper mechanism in which a chain drive assembly transmits oscillation to one end of an arm of the wiper mechanism. Although the drive assembly is enclosed by a housing, no means for sealing the mechanism is provided.
Riggs through U.S. Pat. No. 3618156 describes a power wiper for rearview mirrors which incorporates a complex slot and pinion drive assembly. Again, although the drive mechanism is surrounded by a housing, no means to seal that environment is provided.
Prince in U.S. Pat. No. 3855661 describes an automotive rearview cleaning device. This device incorporates a rotating spirally-grooved rod to drive a wiper arm. The oscillating forces are transmitted from the unsealed drive mechanism to only one end of the wiper. In addition, an external electric motor is remotely mounted on the vehicle. This motor rotates the spirally grooved rod through a flexible shaft and drives the wiper arm through a slidable pin.
DeGraw in U.S. Pat. No. 3866258 describes a wiper assembly. This assembly incorporates hydraulic drive cylinders and a spring return mechanism to drive a wiper through external arms.
Wagenhofer in U.S. Pat. No. 3968537 describes a wiping blade device for truck rearview mirrors. This device incorporates a detachable drive mechanism which is designed to drive a wiper arm from one end of that arm and is designed in such a fashion as to attach to existing mirrors, not as an integral unit.
Jones in U.S. Pat. No. 4212091 describes a wiper apparatus for a viewing surface. This apparatus is hydraulically driven. It includes fluid cylinders and piston rods which are actuated alternatively to create oscillation of the wiper mechanism.
Layton in U.S. Pat. No. 4306328 shows a wiper apparatus including parallel chain drives. These chain drives are not enclosed nor are they in a sealed environment.
Addison in U.S. Pat. No. 4339169 describes a rearview mirror and wiper assembly for vehicles. This wiper assembly is driven by a rotating arm assembly which includes guiding rods and cylindrical housings which are bearing supported. No means for sealing the drive mechanism is described.
Hewitt in U.S. Pat. No. 4459718 describes a fluid pressure operating reciprocating mechanism. This mechanism involves the use of external hydraulic pressure to drive a directional spool in oscillation through the use of selectively switched hydraulic valves.
Finally, DeGideo in U.S. Pat. No. 4457597 describes a self-cleaning side view mirror. This mirror includes a free-floating wiper arm which is designed to be manually moved back and forth as desired.
As these various patents disclose, the simple combination of a mirror and oscillating wiper has been the subject of invention for some time. Prior to the present invention, however, no device has been invented which appropriately combines ease of manufacture, cost of manufacture, reliability, and consumer usefulness. As the mere extent of relevant art indicates, there has been a longstanding recognition that such features in a device is desirable. In spite of this need, the evident lack of commercial success of preexisting devices indicates that the proper combination of manufacturing, cost, and user criteria has yet to exist. None of the existing devices properly address all three of these criteria. While there have been substantial attempts by others, they either have not recognized the need to satisfy all of these criteria or have been unable to combine features in a device which achieves the proper balance. In fact, prior to the most recent patent by DeGideo, which itself is manually operated, there was a clear trend toward increasing complexity by inventors in this field. The present invention not only properly balances the criteria necessary for commercial success, but it also adds many features which add value by either simplifying manufacture, minimizing costs, or enhancing the usefulness of the device.
Generally, the goals of the present invention are to provide a wiping mirror assembly which minimizes manufacturing difficulties, which allows introduction into the marketplace at a most competitive price, and which offers enhanced reliability and consumer features. The present invention accomplishes these goals through many objectives such as providing a wiping mirror assembly which is structurally sound, is available in a sealed package, which utilizes a highly reliable helical screw oscillating mechanism, which is designed so as to utilize inexpensively molded parts, which incorporates a wiper design that can be easily and inexpensively replaced, which may be driven by both electric and pneumatic motors, and in which utilization of a pneumatic motor can actually enhance the sealing characteristics of the sealed environment. Naturally, as is evident from this application, numerous other objects of the invention exist and are described herein.
Since this entire field of invention combines the art of wiping techniques and the art of oscillating drive mechanisms, it is important to note that the present invention offers substantial improvement in even both of these basic fields. In the field of wiping techniques, traditional wiper arms (as are used on almost all automobile windshields) have consisted of spring-loaded mechanisms attached on one end. This is a necessary result of both general aesthetics and the fact that many wiping surfaces consist of compound curves.
As it relates to the present application, traditional techniques are not only unnecessary but are undesirable. Complicated spring mechanisms can be avoided since the surface to be wiped is usually a flat plane. In addition, the structural integrity of the wiper's attachment to the oscillating drive mechanism is enhanced through attachment at both ends. Perhaps one of the most commercially important facets of the present invention is the fact that these improvements have been combined in a way that allows quick and inexpensive replacement of the wiper itself.
As it relates to the field of oscillating drive mechanisms, the present invention utilizes an improved helical screw drive mechanism. The helical screw is designed in a fashion that not only allows easy moldability but enhances reliability through the inclusion of progressively flaired reversing grooves. In addition, the nut and tanged cylinder members which cause the oscillating motion have improved contact area with the helical screw. This further enhances the reliability and durability of such devices.